Somatic GNAQ mutation in the forme fruste of Sturge-Weber syndrome Academic Article uri icon


  • ObjectiveTo determine whether the GNAQ R183Q mutation is present in the forme fruste cases of Sturge-Weber syndrome (SWS) to establish a definitive molecular diagnosis.MethodsWe used sensitive droplet digital PCR (ddPCR) to detect and quantify the GNAQ mutation in tissues from epilepsy surgery in 4 patients with leptomeningeal angiomatosis; none had ocular or cutaneous manifestations.ResultsLow levels of the GNAQ mutation were detected in the brain tissue of all 4 cases—ranging from 0.42% to 7.1% frequency—but not in blood-derived DNA. Molecular evaluation confirmed the diagnosis in 1 case in which the radiologic and pathologic data were equivocal.ConclusionsWe detected the mutation at low levels, consistent with mosaicism in the brain or skin (1.0%–18.1%) of classic cases. Our data confirm that the forme fruste is part of the spectrum of SWS, with the same molecular mechanism as the classic disease and that ddPCR is helpful where conventional diagnosis is uncertain.


  • Hildebrand, Michael S
  • Harvey, A Simon
  • Malone, Stephen
  • Damiano, John A
  • Do, Hongdo
  • Ye, Zimeng
  • McQuillan, Lara
  • Maixner, Wirginia
  • Kalnins, Renate
  • Nolan, Bernadette
  • Wood, Martin
  • Ozturk, Ezgi
  • Jones, Nigel C
  • Gillies, Greta
  • Pope, Kate
  • Lockhart, Paul J
  • Dobrovic, Alexander
  • Leventer, Richard J
  • Scheffer, Ingrid E
  • Berkovic, Samuel F

publication date

  • 2018